In algebraic geometry, an elliptic singularity of a surface, introduced by Philip Wagreich in 1970, is a surface singularity such that the arithmetic genus of its local ring is1.
↑Wagreich, Philip (April 1970), "Elliptic singularities of surfaces", American Journal of Mathematics, vol.92, no.2, The Johns Hopkins University Press, pp.419–454, doi:10.2307/2373333, ISSN0002-9327, JSTOR2373333, MR0291170